Fix string outputs.

Auto collapse for < 2 returns.

lib/abi.js

@@ -251,7 +251,7 @@ var formatOutputAddress = function (value) {
 };
 
 var dynamicBytesLength = function (type) {
-    if (arrayType(type) || prefixedType('string')(type))
+    if (arrayType(type) || type == 'string')   // only string itself that is dynamic; stringX is static length.
         return ETH_PADDING * 2;
     return 0;
 };